The present invention relates in general to a variable electronic component, and more particularly, to a variable trimmer capacitor and variable resistor adapted to provide an operative range of impedance characteristics by operation of an eccentric using an implement such as a screwdriver or the like.
In the advancing technologies of computers, testing equipment, appliances and other fields, various types of hybrid electronic circuits, integrated electronic circuits, micro strip amplifiers, micro electronic systems and other electronic devices are being developed and which are being made on increasingly smaller scale and size than has been known theretofore. In accomplishing this end, the enumerated devices are generally mounted on small flat insulating bases known as substrates. These various devices incorporate or have formed therein or coact with various types of electronic components such as inductors, capacitors, resistors, potentiometers, etc., which in turn must be as small as possible to meet the demands of the reduced scale or size of these devices.
The known prior act miniature devices have reached their functional limit even with the best precision manufacturing techniques because certain elements of these devices cannot be reduced further at reasonable costs for commercially acceptable regularly usable devices. For example, the present known prior art variable trimmer capacitors heretofore used in miniature electronic circuits require a mounting frame and a tuning mechanism. There is a limit as to how these elements can be miniaturized and still provide effective and proper function. Further, the mounting elements and tuning mechanisms, when connected in miniature electronic circuits handling high frequencies create unwanted inductance and capacitance in the systems and devices in which they are used because they form stray current paths when placed in close proximity to each other, as may be required in miniature systems or small electronic designs, thereby producing unwanted circuit interaction such as excessive coupling.
U.S. Pat. Nos. 3,679,940 and 3,757,266, which patents are assigned to the same assignee of the within invention, each disclose variable electronic components, such as capacitors and resistors, which are particularly adapted to meet and overcome the problems of these prior art devices by eliminating the area and mass of conventional mounting frames, tuning mechanisms and other elements heretofore used; and instead integrate the elements of these variable electronic components directly into the circuit. These components are primarily designed as low profile structures exceedingly small in size, simple in construction, easily adjustable, reliable in operation, easily replaceable, and reproducible in quantity without sacrificing uniformity or performance.
However, owing to the exceedingly small size of these variable electronic components, the ability to readily adjust these components have likewise become exceedingly more difficult. These components have been provided with an up-turned tab to be engaged by a suitable adjusting tool, for example, a tweezer, so as to affect the desired operative range of impedance characteristics of the component. As these components become increasingly smaller in size, it can be appreciated that there is a need to provide a more accurate and reliable means for providing the requisite adjustment. To this end, the prior art has included in these variable electronic components a rack and pinion assembly operative upon rotation by a miniature screwdriver. However, the extremely small size of these components have rendered the construction of a rack and pinion assembly having extremely small gear teeth relatively difficult and expensive, subject to breakage and stripping, and thereby rendering its use less than desirable.
Accordingly, it can be appreciated that there is an unsolved need for providing a variable electronic component, such as a variable trimmer capacitor and variable resistor which can provide a desired operative range of impedance characteristics quickly, simply, and inexpensively by adjustment using a suitable implement such as a screwdriver and the like.